Born at Westcombe Park, Blackheath on 9 June 1883, the only son of A G Mackenzie, FIA, and Beatrice E Dell, his wife. He was educated at Eastbourne College, at Emmanuel College, Cambridge, where he graduated after obtaining a third class in the Natural Sciences Tripos, Part I, and at the Middlesex Hospital. At the Middlesex Hospital he gained the junior Broderip scholarship in 1908, and served as house physician and house surgeon. He went to the Royal Infirmary, Bradford, as resident surgical officer in 1913, and was appointed assistant surgeon in 1919 and surgeon in 1923; he was also surgeon to St Luke's Hospital. During the war he received a commission as captain, RAMC, on 10 August 1915, and was sent to No 2 CCS at Bailleuil, first as surgical specialist and afterwards in command. Later he was placed in charge of the 14th General Hospital, BEF, with the temporary rank of major. He was repeatedly mentioned in despatches and was gazetted OBE in 1918. After the armistice he was surgeon in charge of the Bradford Orthopaedic Clinic, Ministry of Pensions. He then resumed his practice and lived at 11 Mornington Villas, Manningham Lane, Bradford. He married Edith A Rice, who survived him with four sons. His third son, Kenneth Bruce Mackenzie, died of wounds in Italy in December 1943, while serving as a lieutenant in the Scots Guards. He died at sea in the SS Duchess of Richmond, 10 February 1934, whilst on a cruise to the West Indies, and was buried in Highgate Cemetery. He left £250 each to Eastbourne College, Middlesex Hospital, and Emmanuel College, Cambridge for an annual prize. Publications:- Differential diagnosis between acute abdominal and certain acute intrathoracic diseases. *Lancet*, 1915, 1, 796. Splint for a fractured humerus. *Ibid* 1916, 1, 674. Observations of fifty laparotomies for gunshot wounds of the abdomen, with G A Stevenson and J J M Shaw. *Ibid* 1916, 2, 173.